Scientific Method• Steps

•Observation•Hypothesis•Experiment•Analysis and Conclusion

If wrong form new hypothesis

Scientific MethodControlled experiment

•Tests effect of a single variable while keeping all other variables the same•Any observed differences should be caused only by the single changed variable

Scientific Method• Observations

(qualitative and quantitative)•Quantitative– involve numbers, counting, measuring objects.•Qualitative– involve characteristics that cannot be easily measured or counted such as color or texture

Scientific MethodHypothesis– a possible explanation, a

preliminary conclusion, or even an “educated” guess about some event in nature

Theory– As evidence builds up, a particular hypothesis may become so well supported that scientists consider it a theory.

Atomic theory

ChemistryOrganic Compounds

•Carbohydrate- main source of energy for animals

•Monomer = monosaccharide (single suger)•Polymer = Starch, Cellulose

•Protein- functional or structural

•Monomer = Amino Acid•Polymer = Protein

•Nucleic Acid-controls inheritance

•Monomer = Nucleotide•Polymer = DNA, RNA

ChemistryEnzymes

•Biological Catalyst•Speeds up chemical reactions•Lowers Activation energy (energy needed to get reaction started

•Not used up during reaction

•A specialized protein •functional protein

ChemistrypH

•Measured on a scale of 1-14

•Below 7 acid

•Above 7 base

•pH of 7 = neutral•Speeds up chemical reactions•Lowers Activation energy (energy needed to get reaction started

ChemistryReactants and Products

water Hydroxide ion

Hydrogen ion

+

H+ H2O OH-

+

Reactants Products

ChemistrySolutions•Solute- “stuff” that is dissolved

•Solvent –the liquid that does the dissolvin

ChemistryChemical bonds– links that hold atoms together. Two main types

Covalent bonds– formed by sharing electrons between two atoms

•Bond found in organic compounds

ChemistryIonic bonds- formed by transfer of 1 more electrons from 1 atom to another

•Ion– (+) or (-) charged atom that results from gaining or losing electron

Cells• Organelles

Nucleus- control center of cell. Contains DNA (genetic material). Found in eukaryotic cells.

Ribosome- organelle where proteins are made. Free-floating and some on Endoplasmic reticulum

Golgi apparatus- Cells “post office”. Packages proteins

Endoplasmic reticulum- Cells transport system. Help make proteins (rough E.R.)

Lysosome- “clean-up” crew of cell. Contains enzymes to break down old cell parts, digest food, etc.

Cell membrane- flexible, and semi-permeable membrane surrounding cell.

Cells• Cell membrane- composed of lipid bi-

layer (2 layers of lipids)Lipid layer also called phospholipids

Cells• Semi-permeable- allows some things to

pass through but not others

Diffusion- movement from areas of high concentration to areas of low concentrations

Osmosis- diffusion of water

Cells• Active transport- takes energy

(endocytosis and exocytosis)

• Passive transport- no energy required (diffusion and osmosis)

CellsProkaryotes and Eukaryotes- Scientists divide cells Into two groups depending on whether they have a nucleus or not.

1. Prokaryotes-no

nucleus

• Smaller and simpler than cells of eukaryotes

• Do have cytoplasm and cell membrane

• Example: Bacteria

CellsEukaryotes- do contain nucleus and membrane bound organelles (includes plants, animals, fungi)

•Contain cytoplasm and cell membrane

•Contains organelles

CellsHomeostasis- maintain constant internal conditions (example: blood sugar levels, blood pressure, shivering/sweating)

Photosynthesis• Equation

• Energy from sunlight converts carbon dioxide and water into high energy sugar (glucose)

• Takes place in chloroplast (organelle)• Affected by:

1. Light intensity2. Amount of water3. Temperature

• Autotroph- Can make their own food (plants)

6CO2 + 6H2O C6H12O6 + 6O2

light

Cellular Respiration• Heterotroph- can not make their own food.

Need to eat something else to obtain energy (fungi, animals, most bacteria

• Equation

• Fermentation- still make energy when no oxygen present. Two types: alcoholic and lactic acid fermentation

• Mitochondria- where respiration takes place

6O2 + C6H12O6 6CO2 + 6H2O + Energy

Cellular RespirationSeries of events: Glycolysis → krebs cycle → electron transport

ENERGY

Cellular RespirationCompared to

Photosynthesis

Cell DivisionCell cycle- series of event cell goes through

as it grows and eventually divides.

Interphase- When cell grows and develops, getting ready to divide again

Mitosis- Division of cell nucleus (forms diploid (2N) cells)

Cytokinesis- cell splits in twoPMAT

Cell DivisionMeiosis- cell division forming sex cells (gametes)

•Results in 4 genetically different cells•Gametes are N (haploid-half the number of chromosomes)

Cell DivisionCell growth (cell gets bigger, volume increases

faster than surface area) so has to divide

DNA, RNA, and Protein Synthesis

• Replication- DNA making DNA• Transcription- DNA making RNA• Translation- RNA making Proteins

DNA, RNA, and Protein Synthesis

DNA RNASugar- deoxyribose Sugar-ribose

Two stranded Single strand

ATCG AUCG

3 kinds of RNA

DNA-double helix

DNA, RNA, and Protein Synthesis

Complementary bases• DNA: C-G A-T• RNA: C-G A-U

DNA, RNA, and Protein Synthesis

Codon- three letter “word” on mRNA specifying a particular amino acid

codon

anticodon

Geneticshomozygous same letters (TT or tt)

heterozygous different letters (Tt)

Genotype- the alleles (letters) i.e. Tt, TT, tt

Phenotype- physical characteristics (Tall, short)

Genetics• Gamete- sex cell (N)

haploid.

• Zygote- fertilized egg

• Fertilization- process when sperm and egg join

GeneticsDominant / Recessive cross- one allele is

dominant over another. I.e. T-tall (dominant) over t-short (recessive)

Tt Tt

Tt Tt

T T

t

t

TT X tt

gametesAll tall offspring

GeneticsIncomplete dominance- one allele is not

completely dominant over another (RR-red crossed with WW-white yields all RW-pink flowers)

RW RW

RW RW

R R

W

W

RR X WW

GeneticsCo-dominance- both alleles are dominant.

RR-red hair, WW-white hair, RW-roan

RW RW

RW RW

R R

W

W

RR X WW

GeneticsDihybrid cross- Mendel’s two-factor

experimental results were very close to 9:3:3:1 ratio predicted by punnett square. Proved that genes that segregate independently do not influence each other’s inheritance.

9:3:3:1

Principle of Independent Assortment

GeneticsMultiple Alleles- ABO blood type is an

example. A and B or co-dominant.

GeneticsCrossing over- when “legs”

of chromosomes cross over each other during meiosis and exchange parts of themselves.

GeneticsNon-disjunction- when chromosomes fail

to separate during meiosis. Resulting in missing or extra chromosomes in gametes

Genetics“Code of Life”- Reading codons and the

amino acids they code for

Example:

CGA UGC AAU

Arg – Cys - Asn

Genetics

CloningCloning- a member of a population of genetically identical cells produced from a single cell

Human ChromosomesHuman Chromosomes- body cells contain 46 chromosomes (23 from sperm, 23 from egg. Join in diploid zygote)

Genetics

•KaryotypeKaryotype- picture of chromosomes cut out from photographs and grouped together in pairs•Sex chromosomesSex chromosomes- two of 46- these determine sex of individual XX=female and XY=male

•autosomesautosomes- remaining 44 chromosomes

Egg cells contain a single X chromosome. Sperm cells contain either one X chromosome or one Y chromosome. Approximately half of the zygotes are XX (female) and half XY (male)

Genetics